Sand blasting the frame can be damaging for electric wires and air lines. I prepped my frame many times, wash it with soapy hot water first remove grease, buy an air needle scaler from Wall Mart attached to truck air supply for thick rusty spots , and some sandpaper rotary tool for the rest, the frame combined with cross members has small surface, not a big deal, you can do it in 5-6 hours.
